Alerting: Add database migration for recording rule fields (#87012)

* Create recording rule fields in model

* Add migration

* Write to database, support in version table

* extend fingerprint

* Force fields to be empty on validate

* Another storage spot, tests for fingerprint

* Explicitly set defaults in provisioning API

* Tests for main API validation

* Add diff tests even though fields are unpopulated for now

* Use struct tag approach instead of FromDB/ToDB hooks as it better handles nulls when deserializing

* test for deser

* Backout RecordTo for now since it's not decided in the doc

* back out of migration too

* Drop datasourceref for now

* address linter complaints

* Try a single outer struct with all fields embedded

pkg/services/ngalert/api/api_ruler_validation.go

@@ -108,6 +108,9 @@ func validateRuleNode(
 		RuleGroup:       groupName,
 		NoDataState:     noDataState,
 		ExecErrState:    errorState,
+		// Recording Rule fields will be implemented in the future.
+		// For now, no rules can be recording rules. So, we force these to be empty.
+		Record: nil,
 	}
 
 	if ruleNode.GrafanaManagedAlert.NotificationSettings != nil {